Many human enzymes serve as targets for the action of pharmaceutically active compounds. Several classes of human enzymes that serve as such targets include helicase, steroid esterase and sulfatase, convertase, synthase, dehydrogenase, monoxygenase, transferase, kinase, glutanase, decarboxylase, isomerase and reductase. It is therefore important in developing new pharmaceutical compounds to identify target enzyme proteins that can be put into high-throughput screening formats. The present invention advances the state of the art by providing novel human drug target enzymes related to the transferase subfamily.
Transferases
The novel human protein, and encoding gene, provided by the present invention is related to transferases in general, specifically sulfotransferases and tyrosylprotein sulfotransferases in particular. Furthermore, the protein of the present invention may be an alternative splice form of tyrosylprotein sulfotransferase 1 (Genbank gi4507665); see the amino acid sequence alignment provided in FIG. 2. The C-terminal sequence is not covered by the genomic sequence, suggesting an additional coding exon.
Tyrosylprotein sulfotransferases are important for catalyzing tyrosine O-sulfation, which is a widespread posttranslational modification that occurs in all multicellular organisms and tissues. The tyrosine O-sulfation reaction involves transferring sulfate from 3′-phosphoadenosine 5′-phosphosulfate to tyrosine residues within acidic motifs of polypeptides (Ouyang et al., Proc Natl Acad Sci USA 1997 Mar. 17;95(6):2896-901). Tyrosine O-sulfation is important in protein-protein interactions in a wide variety of physiological systems, particularly those systems involved in inflammation and hemostasis (Ouyang et al., Proc Natl Acad Sci USA 1997 Mar. 17;95(6):2896-901). Sulfation of tyrosine residues in P-selectin glycoprotein ligand 1 (PSGL-1), a leukocyte adhesion molecule, is required for binding of PSGL-1 to P-selectin on activated endothelium (Ouyang et al., Proc Natl Acad Sci USA 1998 Mar. 17;17;95(6):2896-901). Tyrosylprotein sulfotransferases are integral membrane glycoproteins that are located in the trans-Golgi network with the catalytic site oriented towards the trans-Golgi network lumen. This position allows tyrosylprotein sulfotransferases to catalyze the tyrosine O-sulfation reaction on proteins that pass through the trans-Golgi network, such as plasma membrane and secretory proteins. Tyrosine O-sulfation facilitates protein-protein interactions between such proteins as secretory proteins, cell surface receptors, and plasma membrane proteins. For a further review of tyrosylprotein sulfotransferases, see Beisswanger et al., Proc. Nat. Acad. Sci. 95: 11134-11139, 1998.
Due to their importance in regulating protein-protein interactions, particularly in inflammation, hemostasis, and other important physiological processes, novel human tyrosylprotein sulfotransferase proteins/genes, such as provided by the present invention, are valuable as potential targets for the development of therapeutics to treat inflammatory, hemological, and other disorders. Furthermore, SNPs in tyrosylprotein sulfotransferase genes, such as provided by the present invention, are valuable markers for the diagnosis, prognosis, prevention, and/or treatment of such disorders.
Using the information provided by the present invention, reagents such as probes/primers for detecting the SNPs or the expression of the protein/gene provided herein may be readily developed and, if desired, incorporated into kit formats such as nucleic acid arrays, primer extension reactions coupled with mass spec detection (for SNP detection), or TaqMan PCR assays (Applied Biosystems, Foster City, Calif.).
Enzyme proteins, particularly members of the transferase enzyme subfamily, are a major target for drug action and development. Accordingly, it is valuable to the field of pharmaceutical development to identify and characterize previously unknown members of this subfamily of enzyme proteins. The present invention advances the state of the art by providing previously unidentified human enzyme proteins, and the polynucleotides encoding them, that have homology to members of the transferase enzyme subfamily. These novel compositions are useful in the diagnosis, prevention and treatment of biological processes associated with human diseases.